AES E-Library

A Technique for Displaying the Current and Voltage Output Capability of Amplifiers and Relating This to the Demand of Loudspeakers

The amplifier under test is fed with a large low-frequency sine-wave input on which 50-µs pulses of alternate polarity are superimposed. These pulses drive the amplifier's protection circuits into current limiting, and the setup gives a CRT presentation having current-limit values vertically and instantaneous output voltage horizontally. The displays obtained, which sometimes disclose unsuspected amplifer design faults, are compared with those derived in tests made on loudspeakers using program and other inputs.